Problem: A rectangle has a width of $10$ centimeters. The rectangle's length is $4$ times its width. What is the perimeter of the rectangle?
Solution: Perimeter is the distance around a closed figure. We can find the perimeter of a shape by adding all the side lengths. The ${\text{width}}$ is ${10}\text{ cm}$ and the ${\text{length}}$ is $4$ times the ${\text{width}}$. $4\times10\text{ cm}$ $4\times10\text{ cm}$ $$ $\,10\text{ cm}$ $\,10\text{ cm}$ The ${\text{length}}$ is $4\times{10}={40}\text{ cm}$. $40\text{ cm}$ $40\text{ cm}$ $$ $\,10\text{ cm}$ $\,10\text{ cm}$ Now, we can find the perimeter. $\begin{aligned} \text{Perimeter} &= {\text{ length}} + {\text{ width}} + {\text{ length}} + {\text{ width}}\\\\ &={40}+ {10} + {40} + {10}\\\\ &=100 \end{aligned}$ The perimeter of the rectangle is $100$ centimeters.